Extraction of proteins from total cell lysate is one of the most commonly employed procedures in biomedical research. The first step is to release proteins from the cells by chemical or physical methods. Cell lysis solutions containing denaturing detergents such as SDS, and non-denaturing detergents such as NP-40 and Tween-100 are frequently used in commercial kits for protein extraction (see, for instance, Pierce Protein Research Products, Thermo Fisher Scientific, Rockford, Ill., and PromoKine, Heidelberg, Germany). Though strong detergents such as SDS can lyse the cells efficiently, it also results in a very viscous solution due to the presence of released genomic DNA in the cell lysate, which is difficult to pipette and might interfere with subsequent protein quantification, gel electrophoresis and other downstream applications One of the most widely used laboratory methods to isolate proteins from total cell lysate is to extract proteins using detergent-containing solutions to lyse the cells followed by physical methods such as repeated sonication or passing the cell lysate through a fine needle repeatedly to shear DNA into smaller fragments and reduce the viscosity of the solution; however, these procedures are tedious and time consuming. Repeated sonication also generates significant heat that may inactivate the biological activities of proteins. Affinity purification of desired protein components using spin column filter assembly has been disclosed in U.S. Pat. No. 6,221,655 B1. A variety of commercial manufacturers have adopted the concept and are selling variations of spin column filters either as a stand alone unit or as a component of an assay kit for affinity purification of DNA and RNA (see, for instance, PureLink™ RNA Mini Kit).